The field of aquarium filters has been quite developed because of the many hobbyists and professionals maintaining fish tanks which require that contaminated aquarium water be filtered and decontaminated before it is recirculated into the aquarium tank. Structurally, a filter apparatus is comprised of filtration material in the form of particles of activated carbon or charcoal and a fluffy mass of synthetic resin fibers. Sand or gravel beds are well known materials used in undergravel filters. The filtration material is generally retained within a housing specially constructed for that purpose and the unit may be of the type which is disposed externally of the aquarium tank or within the tank water. In almost all of these, however, an appropriate housing is essential to retain the filtration material, as are means to provide a circulation pathway through which the contaminated water passes and is treated.
Aquarium filters have become quite sophisticated pieces of apparatus and in order to provide both filtration and aeration, complex arrangements have been fabricated. Air lifts and centrifugal pumps comprise the means utilized in aquarium filters to lift and recirculate the aquarium water as it is treated and decontaminated. The housings which are utilized often have complex compartments which typically include a receiving compartment for the contaminated water and a clear water chamber into which the aquarium water from the receiving chamber is caused to flow and in so doing it is caused to pass through filtration materials which decontaminate it prior to being discharged back into the aquarium tank.
Despite the complexity of filter designs, many aquarium filters leave something to be desired with respect to sufficient aeration of the water. Additionally, cleaning of the filter becomes a complicated and often messy procedure. Often filter apparatus must be disassembled so as to gain access to the interior of the housing for its removal and replacement by fresh filter material. The filtration material becomes clogged in a relatively short period of time and the failure to change the material prevents filtration.
In conventional aquarium filtration, the water pressure provided by the pump is sufficient to cause a flow of water through a filter or porous wall so that mechanical filtration of the solid contaminants occurs, the walls acting as a sieve. As waste material accumulates and concurrent biologic action occurs, sludge or slime formation is initiated, and the pores of the filter membrane become clogged and progressively reduce the water flow and consequent filter action. This clogging action continues to the point that flow through the filter wall ceases. The conventional practice is to remove, replace or clean the filter material when clogging has progressed to the point that the flow of water is materially reduced or ceases entirely.
The most effective water purification is achieved at such time wherein the accumulation of waste material serves as a biologic nutrient and sludge formation and biologic bacterial propagation are at a high point. However, at this point excessive clogging of the filter occurs and effective flow and filtration ceases. Replacement of the filter with fresh filter material destroys the most effective environment for maximum aerobic bacterial growth and consequent water decontamination and purification.
Accordingly, although aquarium filters have at times been sophisticated in their designed structure, there is still an unfulfilled need for improvement in the aeration, filtration and water purification capabilities of aquarium filters and the ability to keep the filter in efficient operative condition without requiring frequent maintenance or cleaning.